The purpose of this study is twofold: to test the descriptive validity of current cost (CC) data reported according to SFAS 33, and to examine the relationships of systematic risk to monopoly power and growth potential.The test of the SFAS 33 data was based on the theoretical determinants of Tobin's q ratio, which is defined as the market value of a firm divided by its replacement cost of assets. Whether the SFAS 33 data provide a good measure of current cost can be evaluated by the extent to which the determinants of q explain the empirical q ratios that are derived from this data set.Three determinants of q were identified in the theoretical development. They were (1) monopoly power in the output markets, (2) growth potential in future investment opportunities, and (3) systematic risk. The empirical measures of these three variables were constructed from accounting data. In the regression analysis, they explained about 50 percent of the variation in the q ratios across firms. Thus, the theory for the determination of q was validated and the SFAS 33 data appeared to provide a good measure of current cost.The results were then compared with the tests using both historical cost (HC) and historical cost/constant dollar (HC/CD) data. The CC measures in the SFAS 33 data base were found to be slightly closer to the theoretical replacement cost of a firm than were the HC measures. However, the tests in this study failed to find the superiority of CC measures over thier HC/CD counterparts in approximating the theoretical replacement cost of a firm.The relationships of systematic risk to monopoly power and growth potential were also theoretically examined. It was hypothesized that systematic risk should be negatively correlated with monopoly power but positively correlated with growth potential. The empirical results lent support for the positive correlation between systematic risk and growth potential. The theory for the negative correlation between monopoly power and systematic risk, however, was not substantiated.